Where there's smoke...carbon monoxide exposures in smoking and smoke-free workplaces.

Comparisons of expired air carbon monoxide levels in non-smoking staff in six licensed clubs (a smoking workplace) were made with those of non-smoking staff of a large public hospital (a smoke-free workplace). There was a significant difference between clubs and hospital in levels of CO at end of work. The average concentration of club workers was 8.7 ppm (Hospital, 5.3 ppm). Approximately one third of these non-smokers in licensed clubs exceeded 10 ppm putting them in the 'light smoker' category according to the manufacturer of the monitoring equipment. Club workers increased their CO level during work time by four times the increase of Hospital staff. This study suggests that there are significant gains to be made in reduction of intake of harmful passive-smoking products by removing tobacco smoke from workplaces.